Heat-exchanging fluid circulating apparatus



Filed May 27, 1966 INVENTOR MACH-r28 D m ma m LEON HARD IKATZ ATTORNEY$ United States Patent ,4 'HEAT-EXCHANGING FLUID CIRCULATING I APPARATUS Leonhard'Katz, Woburn, Mass., assignor to Astro Dynamics,'Inc., Burlington, Mass, a corporation 1 of Massachusetts Filed May 27, 1966, Ser. No. 553,333

,Int. Cl. F28f 3/00, 13/12; F24h 3/06 l 5 Claims US. ;Cl. 155-122 The present invention relates to heat-exchanging fluid circulating apparatus, being more particularly directed to cooling boxes suitable for use in electrical and electron c cabinets, housings,'relay' racks and the 'like where it is.

required to circulate cooling air, preferably dustand dirtfree, to keep the various components from overheating during operation. p

Numerous types of cooling devices have been proposed and used throughout the years for such purposes as above mentioned and in other applications. Many electrical and other components have ben directly provided with heatcooling fin" structures as described, for example, in my US. Letters Patent No. 3,216,496, issued Nov. 9, 1965, operating both with and without air fans for carrying away heat radiated by the fins. Such devices are highly effective, but are not particularly useful where the apparatus to be cooled is of considerable size or involves a large number of different types of components; a a" Other approaches more suitable to the last-named circumstances haveinvolved the introduction ofexternal air from the room or other area into the cabinet, housing, or rack and the like to enable such cooling. Apparatus of this type, however, has heretofore required filtering of the air in view of the dust, dirt and other contaminants in the external surroundings. Frequent replacement of filters, indeed, is one of the greatest drawbacks of apparatus of this type.

An object of the present invention, accordingly, is to provide new and improved heat-exchanging fluid circulating apparatus that is not subject to any of the above-described disadvantages; but that, to the contrary, enables the cooling of widely different types of apparatus and equipment contained within the cabinet, housing, or racks without the necessity for attaching cooling fins thereto and without requiring the filtering of external air (or other fluid) that may be used to assist in the cooling operation. In summary, the above ends are attainable by providing a novel structure that enables passing fluid, such as external air, along a first path defined by a set of heat-conducting sheets and circulating a separate fluid, such as the air inside the cabinet, housing or rack, along a second path in heat-exchange relationship with the first path, but independent of and out of contact with the fluid passing along the first path.

A further objective of the invention is to provide a novel heat-exchanging apparatus of more general utility, also.

Still an additional object is to provide a novel fluidcirculating apparatus.

Other and further objects will be explained hereinafter and are more particularly delineated in the appended claims.

The invention will now be described with reference to the accompanying drawing, the single figure of which is a fragmentary perspective of a preferred embodiment, with parts broken away and expanded to illustrate details of construction.

Referring to the drawing, a preferred heat-exchanging fluid apparatus is shown contained within a frame 1 that may, for example, be mounted on the bottom of a cabinet, housing or rack for equipment, generally illustrated by a portion of the frame 3 thereof extending above the frame 1. The frame 1 may be in the form of a rectangular box, the side and bottom walls of which are completely closed off but the top wall of which has a first or rearward open region 1', a second or forward open region 1", and an intermediate closed third region 1", forming a separator plate therebetween. The front :and rear ends of the frame 1 are open, being respectively covered by a front grille 2 and a set of exhausting fans 4.

The heat-exchanging fluid circulating apparatus comprises a plurality of substantially parallel longitudinally extending heat-conducting sheets, 5, 5, 5", 5", 5", 5""', 5""", etc., successively transversely disposed to define longtudinally extending spaces 6, 7, 6', 7, 6", 7", etc. The sheets 5, 5', 5", etc., may be constituted of thin sheet metal or other preferably heat-conducting material, though a high degree of heat conductivity is not required in view of the preferred extreme thinness of the sheets.

Each successive pair of sheets, such as the successive pairs 5-5, 5"5"', 5"5, etc., transversely joined at the forward and rearward ends, the forward ends being respectively shown erimped together at B, 8', and 8", in connection with the three successive pairs above-mentioned. A first set of successive parallel longitudinally extending fluid-circulating paths is formed along spaces 7, 7, 7", etc., between the successive pairs of sheets 5-5, 5"-5", 5""-5" etc. Air or other fluid outside or external to the apparatus 1-3 may thus be drawn in through the thin sheet walls bounding the same and may be controlled by exhausting fans 4 at the back end of the apparatus.

The sheets 5', 5" bounding the space or channel 7 (and the sheets 5", 5" bounding the space 7', etc.) are shown closed ofif along their top longitudinal edges by a transverse strip element 9 (and 9 in the case of the space 7', etc.). Looking from the top downward, therefore, in a direction orthogonal to the longitudinal direction I, a second set of substantially parallel circulating paths is formed by the spaces 6, 6', 6", etc., between the sheets of each pair of sheets 5-5, 5"-5, 5""-5"', etc. Air or other fluid from within the cabinet, housing or rack 3, may be introduced into this second set of paths by a second set of fans: 4', shown angularly disposed above the open region 1 to direct air from inside the cabinet, housing or rack 3 in a direction at least having a component orthogonal to the longitudinal direction I, as shown at II. This inside air is directed into the second set of spaces or channels 6, 6', 6", etc., and, by virtue of the top separator region 1", proceeds substantially longitudinally, as shown at 11', along the spaces or channels 6, 6', 6", etc., and then is recirculated upward, as shown at II", back into the cabinet, housing or rack 23. Because of this flow path, the second set of paths defined by spaces 6, 6, 6", etc., is herein referred to as orthogonal to the longitudinal flow path I. By this construction, the inside air within the cabinet, housing or rack is continuously circulated past the sheets which are being cooled on opposite surfaces by the external fluid passed along the path I. The external fluid, however, with its inherent dust, dirt and contamination, is prevented from contacting or otherwise contaminating the recirculated inside air. The inside cooled and recirculated air thus is independent of and out of contact with the possibly contaminated external cooling fluid, but in heat-exchange relationship therewith. No filters are accordingly required and the apparatus may operate indefinitely without maintenance, insuring the cleanliness of the inside air during its cooling and recirculation.

In some applications, the external cooling air may be at an undesirable temperature; or there may be a need for varying the air velocity within the cabinet, housing, or rack 3. A liquid cooling plate, as shown at 10, may then be provided at the bottom, for example, and the relative air flow along the path I and the path IIII' II" may be varied by controlling the relative voltages applied to the drives of the respective motors 4 and 4' and their input connections 12 and 12. The cooling plate may comprise a zig-zag tube through which cooling fluid is passed and withdrawn, as at 10', or any other suitable cooling device. For optimum operation, the fluid flow along the path I is preferably in the opposite direction to the flow along the path IIII-II".

As an illustration of the eflicacy of the invention, twenty passages of thin sheet metal heatexchanging sheets, approximately 4 /2" high and about 1' long with about spacing for the adjacent sheets, were operated with air flow in each of the paths I and II of approximately 200 c.f.m., allowing only a 1%. C. rise for each 100 watts of heat generated within the cabinet 3.

Further modifications will occur to those skilled in this art and all such are considered to fall within the spirit and scope of the invention as defined in the fol lowing claims.

What is claimed is:

1. Heat-exchanging fluid-circulating apparatus having, in combination, a housing enclosing a chamber therein, a plurality of substantially parallel longitudinally extending heat-conducting sheets successively transversely disposed adjacent to said chamber to define longitudinally extending spaces between the successive sheets, the sheets bounding alternate spaces being transverely joined in pair substantially entirely along both sets of their longitudinal edges to define a first set of substantially parallel longitudinally extending fluid-circulating paths with openings at the ends thereof externally of said chamber, the sheets bounding the remaining spaces being transversely joined in pairs substantially entirely along their ends and being joined substantially entirely along one set of longitudinal edges and along an elongated intermediate region of the opposite set of longitudinal edges to define a second set of substantially parallel fluid-circulating paths having portions orthogonal to the paths of the first set and with openings to said chamber at spaced regions of said opposite set of longitudinal edges, means for passing fluid longitudinally along the first set of paths externally of said chamber, and means for circulating and recirculating fluid along the second set of paths and through said chamber independently of and isolated from the passage of fluid along the first set of paths but in heat-exchange relationship therewith.

2. Apparatus as claimed in claim 1 and in which the fluid-passing means comprises exhausting fan means for drawing external fluid into and out of said first set of paths.

3. Apparatus as claimed in claim 1 and in which the fluid-circulating means comprises fan means positioned to drive fluid into the openings at one of the spaced regions of the second set of paths and to expel the same from the openings at the other of the spaced regions thereof in a recirculating manner.

4. Apparatus as claimed in claim 1 and in which cooling means is provided along said opposite longitudinal sheet edges.

5. Apparatus as claimed in claim 1 and in which means is provided for producing diiferent fluid flow rates in the first and second set of paths.

References Cited UNITED STATES PATENTS 1,409,520 3/1922 Bird 166 X 2,092,835 9/1937 Edwards 165122 X 2,267,905 12/1941 Frantz 165122 X 2,321,110 6/1943 Shipman 165--166 X 2,097,851 11/1937 Wenzl 165-166 X 2,877,000 3/1959 Person 165-466 X 3,363,681 l/1968 Revilock et al. 165-166 ROBERT A. OLEARY, Primary Examiner 0 THEOPHIL W. STREULE, Assistant Examiner U.S. Cl. X.R. 165-166 

